The disclosure relates to a hydrostatic axial piston machine having a cylinder drum which has a sliding surface and therefore together with another component forms a sliding pair.
In axial piston machines, a cylinder drum rotates in relation to a stationary disk-shaped control or distributor plate. Cylinder (bores) are formed in the cylinder drum, and in these cylinder (bores) pistons perform a lifting movement along a lifting direction directed axially in relation to the axis of rotation of the cylinder drum. In the case of an oblique-axis construction, a drive shaft to which the pistons are coupled is set obliquely in relation to said lifting direction. In the case of a swash plate construction, a swash plate to which the pistons are coupled is set obliquely in relation to said lifting direction. The cylinders are connected alternately to a high-pressure side and a low-pressure side of the machine via the distributor plate. In this case, for example, the cylinder drum and the pistons guided therein form a sliding pair within the meaning of the present document.
It is known from the prior art to nitrocarburize the components of sliding pairs and to thereby produce a wear-resistant layer. In this heat treatment method, the chemical composition of the marginal layer is changed, such that the strength is increased and the wear behavior is improved. It is known in this respect to carry out the nitrocarburizing in gas or in a salt bath.
The documents EP 1 122 330 B1 and EP 1 122 331 B1 each disclose a method for nitrocarburizing in gas.
The document WO/0142528 A1 discloses a method for nitrocarburizing an injection nozzle in a salt bath until a connecting layer has reached a thickness of up to 3 μm. Thereafter, the injection nozzle is further treated in a gas nitriding method. The aim of this is to keep the connecting layer thin or in gas nitriding to reduce the size thereof again.
It is an object of the disclosure to provide a cylinder drum of a hydrostatic axial piston machine which forms a sliding pairing with at least one other component—in particular with a plurality of pistons—and the wear-resistant layer of which is more durable and more resistant to failure even at high system pressures and resulting high frictional forces, such that the entire axial piston machine has a high service life.